Title: Bridge Design

Problem Scenario

Did you ever wonder if a bridge is stronger than the other?

Broad Question:

What bridge design can withstand the most weight?

Specific Question:

Would a beam bridge, or arch bridge withstand the most weight?

Hypothesis:

The arch bridge will withstand the most weight.

Graph of Hypothesis

Variables

This graph is about which bridge Design can withtstand the most weight

Independent Variable:

Weight
Dependent Variable:
Bridge design

Variables That Need To Be Controlled:

The material to make the bridges
Span of the bridge
Width of the bridge

Vocabulary List That Needs Explanation

Bridge Design: Arch bridge or beam bridge.
Material for bridges: Popsicle sticks and glue.
Weight: Metal weights,10, 20, 25, and 40 pound weights.
Span of bridge: How long the bridge is.
Width of bridge: The wideness of the bridge.

---

---

---

---

General Plan

I'm going to make two types of bridges (Flat and Arch bridge) out of the same materials (Popsicle sticks) and place weights on the bridges and record which bridge can withstand the most weight.

Potential Problems And Solution

The two bridges wont withstand the weight of the 10 or 20 pound weights. Solution: Get some 5 pound weights than 10 or 20 weights, or reinforce the wooden bridges.

Safety Or Environmental Concerns

There are no safety or environmental concerns for this project.

Experimental Design

What is your experimental unit?

What bridge design can withstand the most weight.

Number Of Trials:

Two

Number Of Subjects In Each trial:

Two

Number of Observations:

I will take eight observations

When data will be collected

I will collect the data after

Where will data be collected?:

The data will be collected in my basement.

Resources and Budget Table

Item	Number needed	Where I will get this	Cost
Popsicle sticks	1000 (max)	Walmart	$6
glue	2	Home	$0
5,10, or 20 pound weights	3-6	Home	$0
Bridge building kit	1	www.Garrettsbridges.com	$45

Detailed Procedure

Step one: I'll Build two bridges out of Popsicle sticks both flat and arch.
Step two: I'll put varied of weights between five-40 pound weights on the span of the bridge.
Step Three: I'll take observations throughout the placing of the weights on the bridges.
Step four:I'll take pictures of a bridge with the weights on them and the bridges broken.
Step five: Do this test another time and record observations and the amount of weight each withstands.

Diagram

Photo List

Two Bridges holding weights.

Time Line

2/1-Procedure, timeline, photo list complete.
2/4-Begin experiments no later than
3/1-Experiments done
3/7- Analysis
3/15-Discussion/background
3/15-Wiki complete
3/22-Poster complete
3/29-KMS fair

---

Data Table

Bridges	Trial 1	Trial 2
Arch bridge	35 lbs.	45 lbs.
Beam bridge	45 lbs.	60 lbs.

---

---

---

---

Data Analysis

All Raw Data

Trial 1
Beam bridge: 45 pounds
Arch bridge: 35 pounds

Trial 2
Beam bridge: 60 pounds
Arch bridge: 45 pounds

Graphs

Photos

Results

My project was to find out which bridge could withstand the most weight, beam bridge, or arch bridge.
My hypothesis was that the arch bridge would withstand more weight than the beam bridge. A beam bridge is the simplest of bridges. It composes of horizontal beams supported by vertical posts. An arch bridge is a bridge with abutments at each end shaped as a curved arch. I took two trials and built two of the same bridge. The beam bridge in the first trial held 45 pounds, and the arch bridge held 35. In the second trial the beam bridge held 60 pounds and arch bridge held 45. That concludes that the beam bridge can hold more weight. I learned that the construction of the bridges is a big factor of how much weight it holds. The arch bridge broke at the glue joints, meaning that the construction wasn't the best. The beam bridge was a little different. It splintered more than the arch bridge and held more weight. If I could do this experiment again, I would've held the clamps on the glue joints for a longer time to make them stronger.

Conclusion

My conclusion is that the beam bridge holds more weight than the beam bridge. My hypothesis was that the arch bridge would withstand more weight than the beam bridge. I rejected my hypothesis. The beam bridge held more weight than the arch bridge.

Discussion

In my project I built two types of bridges (Beam and arch bridge) and tested which could hold the most weight. I hypothesized that the arch bridge would withstand the most weight. I took two trials building two of the exact same bridge so I had two beam bridges and two arch bridges. I was able to answer my question. The beam bridge held more weight.

I think the only problem in my experiment was that I should have clamped the glue joints on the arch bridge for a longer time because when I did the experiment the arch bridge broke at the glue joints, and didn't splinter as much as it should have had.The beam bridge had more splintering because the glue joints held for a longer period of time because it was clamped longer. I think it was a construction problem because the instructions for building the arch bridge didn't say you had to clamp the glue joints. If I had more time for this project i would've done it again so I could clamp the glue joints for a longer period of time and I would've made more bridges for more data.

Benefit to Community and/or Science

My project could help civil engineering. It could help them make the strongest bridges.

Background Research

References

Abstract

In my experiment I built two bridges, arch bridge and beam bridge out of Popsicle sticks. I put weights on the top of the bridges and took pictures of the bridges. The beam bridge held 45 pounds in the first trial. Arch bridge held 35 pounds. Second trial the beam bridge held 60 pounds and the arch bridge held 45 pounds.